Combined pick-off and torquer



Dec. 21, 1965 H. PACKARD 3,225,229

COMBINED PICK-OFF AND TORQUER Filed Aug. 29, 1961 4 Sheets-Sheet 1 FIG. I

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INVENTOR. HENRY PACKARD ATTORNEYS 1965 H. PACKARD 3,225,229

COMBINED PICK-OFF AND TORQUER Filed Aug. 29, 1961 4 Sheets-Sheet 2 fifi m i i? EFF??? F RR? LL J1 l J 35LL 1 LL FIG. 4 47 FIG. 5

INVENTOR. HENRY PACKARD" BY W, W W

ATTORNEYS Dec. 21, 1965 H. PACKARD COMBINED PICK-OFF AND TORQUER 4 Sheets-Sheet 3 Filed Aug. 29, 1961 FIG. 6

FIG. 7

INVENTOR.

HENRY PACKARD ATTORNEYS Dec. 21, 1965 H. PACKARD COMBINED PICK-OFF AND TORQUER Filed Aug. 29, 1961 4 Sheets-Sheet 4 a r I2 27 H Q??? $1 W u SM 3 L. 3 1

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INVENTOR HENRY PACKARD W,Wwm

ATTOR N EYS United States Patent M 3,225,229 COMBINED PICK-OFF AND TORQUER Henry Packard, Norwood, Mass, assignor to Northrop Corporation, Beverly Hills, Califi, a corporation of California Filed Aug. 29, 1961, Ser. No. 134,768 3 Claims. (Cl. 31tl40) This application is a continuation-in-part of my copending application entitled Electromagnetic Transducer, Serial No. 26,831, filed May 4, 1960. Experimental data obtained since the filing of the parent application indicate that the theory of operation of my invention is somewhat different from that originally outlined.

The invention relates generally to electromagnetic transducers and more particularly to an electromagnetic transducer in which the functions of a pickoif and a torquer are combined.

It has become common to utilize pickofis and torquers in conjunction with gyroscopes for navigational or guidance purposes. It has also been proposed to utilize a combined pickoff and torquer in such applications, but problems of a serious nature have arisen. In a specific case involving a rate gyroscope combined with a pickotf of the microsyn type, an integrating gyroscope has been achieved by substituting a conventional torquer for the torsion bar normally used. However, the over-all length of the combined device has tended to be excessive and insufficient space has been available for the longer device. To conserve space, eiforts have been made to combine the torquer and the pickofi in a single unit. These devices are assembled together at one end of the gyroscope and, in theory, the desired result is achieved, but in practice several diificulties are encountered.

Perhaps the most serious of the practical problems arising in connection with combined torquers and pickoffs is the cross-coupling that exists between the torquer and the pickotf. Quite frequently the degree of crosscoupling is so great as to result in a device whose inaccuracy renders it useless in such applications as missile guidance. It is with the elimination of cross-coupling problems despite the combination of a pickoif and torquer in the same volume as a conventional pickotf that the present invention is primarily concerned.

It is, therefore, a primary object of the present invention to improve to a high degree the accuracy of combined torquers and pickoffs.

It is another object of this invention to eliminate cross-coupling which gives rise to inaccuracy in combined torquers and pickofis.

Still another object of this invention is to construct an accurate integrating gyroscope having minimum space requirements.

In general, the invention resides in a novel arrangement of windings and a stator configuration in a transducer by which an output signal and output torque varying as a function of an input quantity may be obtained. Insofar as the pickofi function is concerned, the pickofi primary serves as the excitation coil, and the pickotf secondary coil delivers an output signal to a load. The pickotf primary is wound about alternate pairs of adjacent stator poles, and the pickoff secondary is wound separately about each pole of the pairs on which the primary is wound.

The torquer portion of the device depends for its operation upon additional sets of windings. These windings are arranged symmetrically on alternating sets of poles relative to the pickofi windings and are similarly disposed. The torquer fixed field winding is analogous in its disposition and arrangement to the primary pickotf winding in that it also is wrapped about alternate pairs of adjacent stator poles which lie between the pairs of poles on which 3,225,229 Patented Dec. 21, 1965 the pickotf primary winding is disposed. The torquer control field winding is disposed similarly to the pickofi secondary winding in that it is wrapped about individual poles of the pairs about which the pickoff secondary winding is wrapped. For a better understanding of the present invention together with other and further objects, features and advantages, reference should be made to the following description which should be read in connection with the accompanying drawings in which:

FIG. 1 is a developed view of a portion of a circular stator and the windings disposed upon the poles of that stator in a microsyn;

FIG. 2 is a schematic view indicating the disposition and direction of pickoff windings in the embodiment of FIG. 1;

FIG. 3 is a schematic view of the disposition and direction of windings in the torquer portion of the embodiment of FIG. 1;

FIG. 4 is a schematic view of the flux pattern in the device of FIG. 1, with the rotor at a null position and only the pickoff primary excited;

FIG. 5 is a schematic view of the flux pattern under the same conditions as in FIG. 4, except that the rotor is displaced relative to the stator;

FIG. 6 is a schemaic view of the flux pattern in the device of FIG. 1, where only the torquer fixed field is excited and the rotor is at a null position;

FIG. 7 is a schematic view of the flux pattern under the same conditions as in FIG. 6, but with the rotor displaced relative to the stator;

FIG. 8 is a schematic view of the flux pattern in the device of FIG. 1, with only the torquer control field excited and with rotor at a null position; and

FIG. 9 is a schematic view of the flux pattern under the same conditions as in FIG. 8, but with the rotor displaced relative to the stator.

In FIG. 1, there may be seen a portion of a stator ring 12. The ring is actually circular, but FIG. 1 has been arranged as a developed view to facilitate illustration of the stator and the coils which are wrapped upon it. All of the poles of the stator are not shown, but any integral multiple of eight poles may be used.

Considering first the pickoff portion of the device, there may be seen a coil 14 wound clockwise about adjacent poles 16 and 18. The start of the winding is indicated by the reference numeral 20. The winding continues from the poles 16 and 18 beyond the next two poles to a pair of poles 20 and 22, about which pair it forms a second coil 19, also wound clockwise. Although the winding does in fact continue in similar fashion about additional alternate adjacent pairs of the stator ring, for purposes of the present showing and discussion, it may be considered to terminate at a point 24 beyond the second primary coil.

The pickoff secondary winding has its starting point indicated by reference numeral 26, and it is first wound clockwise into a coil 27 about the pole 16. It continues and is then wound counterclockwise into a coil 29 about the pole 18 from which point it bypasses the next two poles and is wound clockwise in a coil 31 about the pole 20, then counterclockwise in a coil 33 about the pole 22. This secondary may be considered for present purposes also to terminate at the point indicated by the reference numeral 28.

Between the poles 18 and 20 are similar poles 30 and 32. A torquer fixed field winding starting at the point 34 is wound clockwise about the pair of poles 30 and 32 to form a coil 35, from which it continues to the poles 36 and 38 about which it is wound clockwise in a second coil 37. It will be noted that the winding about the poles 36 and 38 is reversed as compared to the winding about the pair of poles 30 and 32 as is more clearly 3 pointed out below. From the poles 36 and 38 the winding continues to terminate at the point 40.

The torquer control field winding originates at point 42, is first wound clockwise about the pole 30 to form a coil 39, then counterclockwise about the pole 32 to form a second coil 41. It passes then to the pole 38 about which it is wound counterclockwise into a coil 43, and finally to the pole 36 about which it is wound clockwise to form a coil 45. The winding terminates at a point 44. A rotor 47 is, of course, included in the total structure, and it is shown fragmentarily in this view to permit a clearer understanding of the various windings, their directions and operative interrelation.

In the schematic showing of FIG. 2, the winding directions of the pickofi portion of the device and their significance may be more easily visualized. The primary or excitation winding of the pickofl' originates at the point and is formed first as a relatively long clockwise wound coil 14 which is the coil about the adjacent pair of poles 16 and 18. It is then shown as being wound clockwise in a relatively long coil 19 about the adjacent pair of poles 20 and 22. The winding terminates at the point 24. The rotor of the device is schematically illustrated by the laminations and arrow 47.

The secondary or output winding of the pickofi portion of the device is shown as originating at the point 26. The first coil 27 is formed about the pole 16 and is wound in a clockwise direction. The second coil 29 is formed about the pole 18 and is wound in a counterclockwise direction. The third coil 31 is wound about the pole 20 in a clockwise direction, and the fourth coil 33 is wound about the pole 22 in a counterclockwise direction. The winding terminates at the point 25.

In the torquer portion of the device, the fixed field winding originates at the point 34 and is first wound about the adjacent pair of poles and 32 in a clockwise direction to form the coil 35. It is then wound clockwise about the poles 38 and 36 in that order to form the coil 37, running in the opposite direction to the coil 35. The winding terminates at the point 40.

The torquer control field Winding originates at the point 42 and is first wrapped in a clockwise direction about the pole 30 to form the coil 39. It is then wound about the pole 32 in a counterclockwise direction to form the coil 41. It then continues to the pole 38 about which it is wrapped in a counterclockwise direction to form the coil 43, thence to the pole 36 about which it is wrapped in a clockwise direction to form the coil 45. The winding terminates at the point 44.

In FIG. 4, the same section of the stator ring 12 and the rotor 47 are shown. The rotor is in a null position relative to the poles and the pickofi primary coils are excited. Under these conditions, the flux paths which are set up are illustrated. Considering the torquer portion of the device, the poles 30, 32, 36 and 38 are of present interest. In the torquer fixed field winding, there is induced in the coil a voltage 26. A voltage -2e will be induced in the coil 37 because it is wound in series opposition to coil 35. Therefore, the total induced voltage in the torquer fixed field equals 2e2e=0. In other words, no cross-coupling exists.

In the torquer control field winding a voltage e is induced in the coil 39, and a voltage -e is induced in the coil 41 on the pole 32. This result obtains because the coil 39 is wound in a clockwise direction, and the coil 41 is wound in a counterclockwise direction. A voltage e is also induced in the coil 43 on the pole 38, and a voltage --e is induced in the coil 45 on the pole 36. As is indicated, thecoils 39 and 45 are wound inv a clockwise direction, and the coils 41 and 43 are wound in a counterclockwise direction, but the pair of coils 39 and 41 are wound in series opposition to the pair of coils 43 and 45. The total induced voltage in the torquer control field equals ee+ee=0. Again, no crosscoupling exists.

In FIG. 5, the rotor 47 is shown in a displaced position relative to the stator ring 12. Once again, the voltage induced in the torquer fixed field equals 2e2e=0. The voltage induced in the torquer control field winding equals -2e--(2e)=0. Thus, no cross-coupling exists in the condition where the rotor is displaced. This result obtains in the situation illustrated in FIG. 5 insofar as the torquer fixed field is concerned because of the winding of'the two clockwise coils 35 and 37 in series opposition as in the situation illustrated in FIG. 4. On the other hand, the result achieved in the torquer control field occurs because the winding 41 is in a counterclockwise direction as is the winding 43. Reverting for the moment to FIG. 3, it may be seen that these windings are also arranged in series opposition. The doubled voltage as compared to the voltage induced in the same coils in FIG. 4 exists by virtue of the doubled flux linkage in both coils 41 and 43. The efiects, however, are cancelled.

In FIG. 6, excitation is applied only to the torquer fixed field. In this instance, no flux links any of the pickoff windings 14, 19, 27, 29, 31 or 33, and therefore, no cross-coupling can exist.

In FIG. 7, even though the rotor 47 is displaced relative to the stator ring 12, there is again no flux linking any of the pickofi windings 14, 19, 27, 29, 31 or 33, with the same result, namely that no cross-coupling exists.

In FIG. 8, only the torquer control field is excited. Once again, no flux links any of the pickofi windings 14, 19, 27, 29, 31 or 33. Thus, with the rotor at a null position relative to the stator, the absence of linking flux results in no cross-coupling.

In FIG. 9, the displacement of the rotor does not disturb the situation insofar as the pickoff windings are concerned. It is obvious from an examination of the illustrated flux pattern that no flux links the pickotf windings. Therefore, in this situation there is no cross-couling. p Operation of the present invention is obvious from an examination of the illustrated structures and schematic diagrams. Electrical cross-coupling is completely eliminated between the pickofi and torquer sections of the device. Application of a signal to the torquer control field will cause the rotor to turn in the same manner as in a conventional microsyn torquer. That is, rotor displacement in response to a signal of given phase and amplitude will be in a direction and of a magnitude determined -by the phase and amplitude of the applied signal. Also, of course, reversal of the phase of the signal will result in reversal of the direction of rotation of the rotor. Similarly, operation of the invention as a pickoif is also the same as that of conventional microsyn pickoifs. The output signal derived from the pickoif secondary will be determined by the position of the rotor relative to the stator. Moreover, the device may operate alternatively as a pickoff or torquer or it may operate simultaneously as both pickoff and torquer.

Various modifications in the details of the structure such as changes in numbers and disposition of poles in the stator or rotor or the use of translational rather than rotational relative movement by the rotor and stator elements will suggest themselves to those skilled in the art upon a reading of the foregoing specification. These and other similar alternatives fall within the purview of the invention, and accordingly, the invention should be limited only by the spirit and scope of the appended claims.

What is claimed is:

1. In a combined pickotf and torquer, a stator having a plurality of salient poles, a rotor disposed for movement relative to said stator, a pickofi primary coil wound on at least a. first pair of adjacent poles of said stator, a pickoff secondary coil wound on each of the individual poles of said first pair of adjacent poles, a torque-r fixed field coil wound on at least a secondary pair of adjacent poles of said stator, said first pair of poles being adjacent said second pair of poles, and a torquer control field coil wound on each of the individual poles of said second pair, said pickoff secondary coils being wound in opposite directions and said torquer control field coils being wound in opposite directions whereby cross-coupling between said torquer coils and said pickotf coils is eliminated.

2. In a combined pickofi and torquer, a stator having a plurality of salient poles, a rotor movable relative to said stator disposed adjacent and in operative relationship thereto, a pickofi primary winding in the form of coils Wound about first alternate adjacent pairs of said poles in series-adding relationship, a pickofi secondary winding in the form of coils wound about individual poles of said first alternate adjacent pairs, said coils of said pickoif secondary winding being wound alternately in opposite directions, a torquer fixed field winding in the form of coils wound about second alternate adjacent pairs of said poles in series-opposing relationship, said second alternate adjacent pairs of poles lying between said first alternate adjacent pairs of poles, and a torquer control field winding in the form of coil-s wound about individual poles of said second alternate adjacent pairs, the first of said coils of said torquer control field winding being wound in a given direction, the second being wound in a direction opposite said given direction, the coils on the individual poles of each pair being in series-opposing relationship to the coils on the individual poles of the next pair of said second alternate adjacent pairs.

3. In a combined pickofi and torquer, a stator having a plurality of salient poles, a rotor disposed for movement relative to said stator, pickofi primary and secondary coils wound on certain of said poles, torquer fixed field and control field windings wound on others of said poles, means for exciting said pickofi? primary coil, and means for exciting said torquer control field winding, said torquer control field and fixed field windings being disposed upon said other poles such that no cross-coupling exists between said torquer windings and said primary pickoff coil during excitation thereof, said pickofr" coils being disposed upon said certain of said poles such that no cross-coupling exists between said pickofi coils and said torquer control field winding during excitation thereof.

References Cited by the Examiner UNITED STATES PATENTS 2,669,126 2/1954 Simmons et a1. 336 X 2,814,743 11/1957 Johnson 336-435 X MILTON O. HIRSHFIELD, Primary Examiner. 

1. IN A COMBINED PICKOFF AND TORQUER, A STATOR HAVING A PLURALITY OF SALIENT POLES, A ROTOR DISPOSED FOR MOVEMENT RELATIVE TO SAID STATOR, A PICKOFF PRIMARY COIL WOUND ON AT LEAST A FIRST PAIR OF ADJACENT POLES OF SAID STATOR, A PICKOFF SECONDARY COIL WOUND ON EACH OF THE INDIVIDUAL POLES OF SAID FIRST PAIR OF ADJACENT POLES, A TORQUER FIXED FIELD COIL WOUND ON AT LEAST A SECONDARY PAIR OF ADJACENT POLES AND SAID STATOR, SAID FIRST PAIR OF POLES BEING ADJACENT SAID SECOND PAIR OF POLES, AND A TORQUER CONTROL FIELD COIL WOUND ON EACH OF THE INDIVIDUAL POLES OF SAID SECOND PAIR, SAID PICKOFF SECONDARY COILS BEING WOUND IN OPPOSITE DIRECTIONS AND SAID TORQUER CONTROL FIELD COILS BEING WOUND IN OPPOSITE DIRECTIONS WHEREBY CROSS-COUPLING BETWEEN SAID TORQUER COILS AND SAID PICKOFF COILS IS ELIMINATED. 